Currently, dispersion-based colorants, such as universal colorants, are packaged in quart metal cans. The metal cans require a variety of tools to be opened in order to fill colorant dispensers. Such colorant dispensers are used to provide one or more colorants to a base paint to provide a paint of a desired color. A common method used to open the metal cans of universal, dispersion-based colorant is with the use of a carpet knife and a “church key” type triangular can opener. This method of opening the cans has exposed those employees who formulate the paint for the individual consumer to potential injury. Additionally, both opening tools and methods of use leave small openings in the top of the can from which the colorant has to be poured. This results in slow addition time to the dispensers, does not allow the metal containers to fully empty, and does not allow for access to properly clean the containers for environmentally sound disposal.
In the daily filling of the colorant dispensers, a large number of quart containers are required. This process of refilling the dispensers requires a considerable time commitment. Typically, prior to filling the dispensers, the containers holding the colorant are shaken, such as in conventional paint mixing equipment, to mix and provide a uniform colorant. Mixing in such equipment takes about 3-5 minutes. If a full quart of colorant is not used, the containers are stored until the next day. There is no way to reseal the partially filled open containers, subjecting the containers to potential contamination, spillage, evaporation of components, and inability to remix. Upon completion of filling all dispensing canisters, all the quart cans are disposed of as normal waste. There is no ability to recycle.
“Plastics Technology—Online,” October 2003, discusses new technology to replace the ubiquitous one-gallon metal paint cans used by professional painters and household consumers. From the article is described the Sherwin-Williams Dutch Boy “Twist and Pour” gallon plastic can, an extrusion blow molded HDPE container with a PP lid that is presently commercialized. This advance was reinforced by the introduction of a similar container by Masterchem, a supplier of primer paints that sells topcoats in gallon and quart HDPE cans. These plastic containers are square-bodied, rounded-lid, twist-top designs that fit more cans into available shelf space, a priority for mass retailers. The new plastic containers also incorporate ergonomic and convenience features for the predominantly female paint consumer, including injection molded handles and pour spouts, a recloseable screw cap that doubles as a paint cup, and color-coordinated labels that help consumers pick the right paint. However the new multi-part containers cost at least three times as much as the typical steel gallon can. Further, the new plastic paint containers fit awkwardly into the paint industry's current handling, filling, and tinting infrastructure designed for round steel cans.
In early 2004, two firms are to launch new all-plastic concepts for direct replacement of metal cans: an injection molded opaque, all-PP can developed by KW Plastics of Troy, Ala., and an injection stretch-blow molded clear, one-piece PET can from the PCC Group in the U.K. For about a decade, KW Plastics has supplied mass-market paint companies with millions of paint cans in a hybrid design that joins a PP body to a steel ring and lid. KW now plans to launch an all-PP paint can by mid-2004. The can body, ring, and lid will be of black, high-impact PP, though at first it will still have a snap-in metal handle. The can's crush-resistance reportedly exceeds that of metal cans and is sufficient to stack containers up to 25 units high. Called “Snap Lock,” the two-part gallon can uses an injection molded black PP body similar to that of hybrid cans and a separate injection molded PP ring and lid. The shape of the can intentionally parallels that of the steel version so that it can fit easily into existing filling lines and in-store shaker equipment. Injection molded, snap-in PP pour spouts and handles are also in development.
The present applicants are not aware of any patents regarding alternative containers to address colorant handling issues. Sherwin-Williams offers colorant in a “F” style one-gallon plastic container. The “F” style container is a duplicate of a gallon anti-freeze container. In order for the colorant to be mixed, this container must be hand shaken. Those instructions are specified on the label. It appears that no provisions have been made for this container to be shaken with paint shaking equipment.